In injection molding machines, conditions for the temperature control of a heating barrel are one of important management elements that influences the quality of resin molding products to be obtained. The temperature control of this heating barrel is performed by feedback control on the basis of proportional integral derivative control (PID control), as described in, for example, PTLs 1 and 2. Incidentally, PTLs 1 and 2 suggest that temperature control adapted to a thermal state change of a temperature control system can be performed by switching PID parameters at the time of an operation step of an injection molding machine and switching of a state.